1. Field of the Invention (Technical Field)
The present invention relates to high performance, high velocity, hard target penetrating warhead cases and other high velocity projectiles, such as anti-armor devices.
2. Background Art
In order to achieve significant penetration performance increases over conventional high strength steel warhead cases, high density structural alloys such as tungsten heavy alloys (WHA) and/or the boosting of the warhead to high impact velocities have been employed. WHA alloys are metal-matrix composite materials with compositions of about 80% to 97% by weight tungsten with the balance being some combination of nickel, iron, and/or cobalt. During the liquid phase sintering (LPS) consolidation process, the tungsten forms into small solid particles surrounded by a liquid, steel-like matrix alloy composed of the nickel, iron, and/or cobalt with a substantial amount of dissolved tungsten.
The drawbacks of using LPS WHA are that high strength necessary to survive oblique impact conditions is difficult to achieve and the hardness of the material is low. The use of velocities significantly higher than the 1000 to 1100 ft/s typical of ballistic warheads results in erosion of the nose surface in both steel and WHA cases due to melting and hot shearing of the nose material. This erosion leads to loss of penetration performance and possible deviation from a straight path due to erosion asymmetry.
The present invention provides materials and methods of manufacture that overcome the above problems and provides a non-eroding, high performance penetrator capability.